Changing spark plugs

[Rottbott]

Well, seems my plugs may not have been changed in the last 50,000 miles for all I know, since I've overlooked it the entire time I've had my car. Might explain its reluctance to start :). I got a new set, but is there anything I need to know about fitting them? The workshop manual gives a torque but I don't have a torque wrench so I'm just going to be guessing about that. Is it particularly important? And do I need to adjust the gap on them?

[steve.s]

hi

i did mine a while ago, with my air intake off.

i can't remember if you have to move the fuel distributor.
but everything is a bit tight.

i put a release oil down the plug holes for a few days each day prior to removing. personally i don't like wd40.
i also put a small straw duck taped to a hover to suck up anything prior to removing to plugs.

mine had bits of twigs!.

so the holes were nice and clean.

then remove the old ones carefully as they can break. mine broke a ceramic part and make sure no bits drop down the hole.

the new ones i use a small amount of copper grease on the thread.
just make sure non drops down the hol or gets on the gap area.

i checked the gap on mine with a feeler guage, but they were ok.

with my hover, no hoover :lol: conversion i also clean all other nooks and cranies in the engine as mine had been parked under a tree.

[NickT]

As steve.s Said !

I used WD40 and an airline though but same thing applies.

I have got Bosch HR6DC in mine. Gapped to 0.65mm

Take time re-inserting the plugs and take care not to cross thread them.

You can access all of the plugs with a 12" long 3/8 extension bar and a t bar with a slimline spark plug socket on the end.

I'd recommend pulling the weather shield on the spark plug lead prior to refitting the plug ends. This way you can ensure you get a positive connection on the spark plug before sliding the weather shield back down. A little spray of silicone lubricant helps a bit here.

Enjoy

NickT.

[NickT]

I forgot to say that remove the air filter and trunking to get easy access to the right three plugs

The left 3 plugs are a bit more awkward, the back one will have easier access with the idle speed motor removed.

Some cars have the metal coolant pipe going over the bottom left spark plug that can make it a little more time consuming.

NickT.

[Rottbott]

Thanks for the tips. I'll get some WD40 down there ASAP and try removing the plugs in a few days. I'll probably move the AC compressor as well as the air filter to make it easier to get at stuff. I actually changed the coil->distributor lead today (and wow that thing is hard to get at!) and the car now starts fine (yipee), but I'm sure the plugs need doing anyway after all this time and mileage.

[NickT]

you don't have to move the ac compressor

a long 3/8 extension bar will fit

[Kinchan]

I asked NGK info about...

Hello,

The difference between Laser Iridium and Iridium IX is mainly in the
ground electrode. Laser Iridium spark plugs will have an area of
platinum on the ground electrode to provide a longer service life for
the spark plug because of the durability of both Platinum and Iridium.
Iridium IX spark plugs are performance designed spark plugs and have a
taper cut ground electrode shape for better ignitability and engine
performance. There is not any platinum on the ground electrode of an
Iridium IX spark plug. Although the Iridium IX plug may outperform a
Laser Iridium spark plug, it will not out last it. Replacement
intervals are determined by the engine manufacturer and modifications
and engine condition may have an effect of plug life.

There is also a difference between these plugs with the preset gap.
TR5IX will come out of the box gapped at .040" while ITR5F13 is preset
to .052". The recommended gap according to my notes for this vehicle is
.030". I suggest TR5IX to get the closest to this setting. If you plan
on adjusting any fine wire spark plug, please take caution not to use
anything that will pry or put pressure against the center firing
electrode as plug damage can occur. Thank you.

Kristopher Zdral
Technical Support Representative
NGK Spark Plugs (U.S.A.), INC.

http://www.ngksparkplugs.com/part_finde ... neid=10549

[TheOriginalMrP]

This is a job that I'm putting off too Rob.... I also noticed the difficulty in changing leads, as I have a Spitfire multispark coil to distributor lead that is waiting to be fitted. I heared these cure a lot of starting problems because of a cleaner more efficient spark, but I know there will be a few sceptics out there..... I gave up after a quick look. Let me know how you get on with the plugs, and I can notify my fitter of the techniques!!!

Hope it goes ok for you....

Ben

[NickT]

If you are refering to the spark gap that goes in line of the main (king) ht lead then I am one of those sceptics with my background in physics
(I would do a comparison before and after as a scientific experiment on a well tuned engine with the ignition system in good working order)

Anyway, you can get to the distributor cap without removing the inlet manifold if you:

disconnect the throttle spool to throttle plate link rod
remove the intake manifolds W pipe
unbolt the 19mm banjo bolt fuel line from the fuel distributor (right hand side)
remove the venturi to inlet manifold mounting bolts
lift the whole ventury up and forwards
with long arms and leaning over the engine you can now access the distributor cap and leads etc.

(obviously de-pressurise the fuel system and isolate the electrics by disconnecting the cars battery first!)

NickT.

[Rottbott]

This turned out pretty easily in the end. None of the plugs were very stiff, and all could be accessed with a standard bar as Nick said. The only difficulty was that the idle speed thingy had to be moved (by undoing two alan key bolts) so that I could reach in to reconnect the lead after changing the left-rear plug.

Car finally starting and running perfectly again. :)

[ChrisS]

Not that difficult to change the king lead or get to the dizzy cap, like Nick said you can just get enough room to change HT leads by lifting the air flow sensor body but personally i 'flip' the whole unit to the left by undoing the + & - fuel lines, undoing the FV from the RH cam cover, popping out the 3 injectors ect ect. and takes no longer than Nick's method, all that fumbling and my fat hands

[NickT]

Rottbott Wrote:This turned out pretty easily in the end. None of the plugs were very stiff, and all could be accessed with a standard bar as Nick said. The only difficulty was that the idle speed thingy had to be moved (by undoing two alan key bolts) so that I could reach in to reconnect the lead after changing the left-rear plug.

Car finally starting and running perfectly again.

What were your old plugs like?
Were they past thier best and/or black/sooty on the centre electrode?

NickT.

[Rottbott]

They were platinum ones but had been in for a long time. They weren't too bad really, a little bit sooty but not in the middle. The coil lead made a lot more difference but it can't hurt to overhaul the whole lot.